Boom system for oil containment

ABSTRACT

An improved boom system for the containment of oil spills on the surface of water, essentially comprising a multiplicity of intercoupling cells comprising floatatable material, open at top and bottom, forming an in-depth barrier that is wave conformal, the barrier being appropriately stabilized by weights and being coupled to a tether boom, which, in turn, is connected to moorings. Oil carried over the barrier face by waves is trapped in the cells as is oil carried under the barrier face by current flow.

United States Patent Nugent [54] BOOM SYSTEM FOR OIL CONTAINMENT [72]Inventor: John B. Nugent, Winthrop, Mass.

[73] Assignee: Massachusetts Institute of Technology, Cambridge, Mass,

22 Filed: Jan. 13,1971

21 Appl.No.: 106,225

[52] US. Cl ..6l/l F [51 Int. Cl. ..E02b 15/04 [58] Field of Search..6l/1 F, 5

[5 6] References Cited UNITED STATES PATENTS 3,597,924 9/1971 Risin..6l/l F T0 ANCHOR ei (Y CURRENT 1 [451 Nov. 21, 1972 2,658,350 11/1953Magill ..61/5

Primary Examiner-Peter M. Caun Attorney--Thomas Cooch, Martin M. Santaand Arthur A. Smith, Jr.

[57] ABSTRACT An improved boom system for the containment of oil spillson the surface of water, essentially comprising a multiplicity ofintercoupling cells comprising floatatable material, open at top andbottom, forming an indepth barrier that is wave conformal, the barrierbeing appropriately stabilized by weights and being coupled to a tetherboom, which, in turn, is connected to moorings. Oil carried over thebarrier face by waves is trapped in the cells as is oil carried underthe barrier face by current flow.

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TO ANCHOR T i l INVENTOR 1 JOHN B. NUGENT ATTORNEY BOOM'SYSTEM FOR OILCONTAINMENT BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates generally to anti-pollution apparatus and moreparticularly to a new and improved boom system for the containment ofoil spills on water.

2. Description of the Prior Art Oil spills on water are the result ofaccidents occurring during the production, distribution, and consumptionof crude oil and its derivatives. Mostsuch accidents involve shiploading and unloading, groundings and collisions and, to a lesserextent, offshore drilling blowouts and pipe fractures. The oil fromthese spills floats on the surface of the sea in patches called slicks.There are a number of different approaches to this problem, includingthe use of chemical emulsifiers, collectors, air barriers, and booms,described in considerable detail in the literature.

Of these various approaches, oil booms are in common use today in anattempt to contain oil spillage. A 1

major disadvantage of presently available oil booms, however, lies inthe fact that oil may be carried over the boom by waves and under theboom by currents. In fact, a review of the literature indicates that oilbooms are generally ineffective in sea states over about 2 to 4 feet andin currents over 0.7 knot. Hence, booms available to date are effectiveonly under conditions of very calm sea (little waves) and very lowcurrent.

SUMMARY In view of the foregoing limitations existing in the presentlyavailable booms used to contain oil spillages on water, it is a generalobjectof the invention to provide a simple, effective, and inexpensiveboom system that is capable of oil containment despite relatively heavysea states and/or strong currents. 7

It is another object of the invention to provide a boom system that isdesigned to form a wave conformal in-depth barrier such as to containoil driven over the face of the barrier by waves or under the face ofthe barrier by currents.

These and other objects are met by a boom system comprising amultiplicity of cells, open at top and bottom, interconnected to form ahorizontal in depth barrier called the oil boom which, in the preferredembodiment, resembles a honeycomb and which is designed to be waveconformal. The cells are constructed of membrane-like plastic materialand floatation, and are designed to form pockets for the collection andcontainment of oil. The oil boom or barrier, in turn, is coupled to atether boom which is attached to moorings. The oil boom is partiallysubmerged as is explained in the specification. Oil washed over the faceof the oil boom or carried under it is trapped in the pockets or cellstowards the top of which the horizontal velocity is considerably lessthan the current, preferably zero, despite the state of the sea or themagnitude of the current.

Further objects, features and advantages of the present invention and abetter understanding thereof will become apparent in the followingdetailed descrip tion taken in conjunction with the accompanyingdrawings.

DRAWINGS FIG. 1 isa plan view of the overall invention.

FIG. 2 shows one of the cells comprising the oil boom or barrier of FIG.1.

FIG. 3 is a vertical section of the invention of FIG. 1.

PREFERRED EMBODIMENT As shown in FIG. 1, the preferred embodiment ofsubject invention comprises oil boom or barrier 20 coupled vialines 9 totether boom 10 which, in turn, is attached to mooring floats 4 viamooring pennants 3. Oil boom 20 comprises a multiplicity of cellsinterconnected so as to give the appearance of a honeycomb design. Inthe preferred embodiment, moorings comprised of anchors 6, lines 5,floats 4 and pennants 3 maintain the tether boom in the I desiredlocation. Tether boom 10' comprises a series of lightweight plasticfloats strung together in a line at spaced intervals. In the preferredembodiment, the floats are 6 inches indiameter and 2 feet in length.

Referring now to FIG. 2 in conjunction with FIG. 1, each of cells 100comprises three sheets of plastic membrance material arranged in atriangular configuration and coupled together at eachvertex of thetriangle via floats 120. (It is understood that the cells may take othershapes such as hexagonal, for example, as long as the desired pocketsare formed.) In the preferred embodiment membrane sheets 110 areconstructed of reinforced plastic, i.e., woven fabric coated withplastic, and approximately three feet by 3 feet in dimension. Floats areformed of a plastic such as polyethylene and are cylindricallyconfigured, having a diameter of three inches and a vertical length of 3feet. Suspended from the bottom of each of floats 120 is a weight 12]designed to keep the cells essentially in the vertical position relativeto the surface of the water. Oil boom 20 is located in the wateraccording to a preferred ratio, to wit, twice as much of cell 100 issubmerged as it is above the surface of the water. In the case of thepreferred embodiment, cell 100 is located such that one foot projectsabove the water, leaving 2 feet submerged.

Vertical stability is of considerable importance to the operatingefficiency of the boom system. Such stability is achieved in thepreferred embodiment as shown in FIG. 3. As noted therein, each float120 has suspended therefrom a weight 121. Further, floats 120 arecoupled via membrance sheet 110. Additional stability is effectedthrough the use of line pairs 9a and 9b coupled at one end to the topand bottom of each of floats 120 comprising the barrier face and coupledat the other end to tether boom 10, which, in turn, is coupled to largemooring floats 4. The overall effect is such as to maintain the oil boomface essentially vertical relative to the surface of the water whilesimultaneously preventing oil boom 20 from being totally submerged dueto strong currents and enabling it to be wave conformal.

Referring now to FIGS. 1 through 3, the improved boom system operates asfollows. Where there is both wave motion and current flow, the oil iscarried along the surface of the water until it reaches oil boom orbarrier 20. High wave action causes water and oil to spill over thebarrier face into the pockets or cells 100. If

there is also a strong current, a certain percentage of the oil isentrained or carried under barrier 20. As the current flows under thebarrier, however, the oil exhibits a tendency to rise up into thepockets of water formed by cells 100. As the oil is carried along underthe barrier, a certain portion is trapped by each of the succeedingcells. As aforementioned, the horizontal velocity of the water towardsthe top of the cells is considerably less than the current, preferablyzero. Because of this velocity condition within the cell and because ofthe natural tendency of the oil to rise above water, the oil trapped inthe cells remains contained therein unaffected by the current flow to bywave motion. The contained oil can then be removed by pumping or othermeans.

As is known in marine engineering, the velocity/turbulence of watertrapped within the cells will be a function of a number of factors,including the depth of submergence of the cells, the size and shape ofthe cells relative to the submergence, the spacing between cells in thebarrier, and the velocity of the current.

It is understood that a number of possible variations to the abovedescribed apparatus are contemplatedwhile still remaining within thescope of the invention. For example, although specific types of materialwere mentioned for the preferred embodiment it is only necessary thatthe material used exhibit proper floatation characteristics for buoyancyand be sufficiently flexible to enable the system to be wave conformal.Further, it is understood that oil boom or barrier 20 may be coupled inany of a variety of ways to the tether boom which, of course, may alsoassume a number of possible configurations as described in theliterature. For example, the tether boom is in no way limited to theparticular float configurations described in the preferred embodiment,and, in fact, most available tether booms would work equally well. It isalso contemplated that the floats and weights may be integrated, to wit,the weight may be inside of and at one end of the float, resulting in aballasted, vertically stable float. Further, the cells may take anyshape conducive to forming the desired pockets. Where the invention isto be used for reversing current, the invention will functionefficiently merely by coupling a second tether boom to the other side ofbarrier 20 such that barrier 20 is then strung between two tether booms.

Having thus described my invention, I claim:

1. An improved boom system for the containment of oil spills on thesurface of water, comprising in combination:

a. A first boom comprising a multiplicity of cells interconnected so asto form a weblike barrier having vertical and horizontal dimensionrelative to the surface of said water, said barrier comprising at leasttwo horizontal rows of said interconnected cells, each of said cellsbeing open at the top and bottom and comprising a vertically extendinghollow segment of floatatable material, said barrier being designed suchthat, upon partial submergence, the horizontal velocity of water towardsthe top of said cells is considerably less than the current;

weights coupled to said fist boom for maintaining said first boompartially submerged in said water;

c. a tether boom tied to said fi t boom; d. by lines which connect s aid first boom to said tether boom such as to maintain said first boomessentially vertical relative to the surface of said water; and

e. mooring means coupled to said tether boom.

2. An improved boom system for the containment of oil spills on thesurface of water, comprising in combination: I

a. A first boom comprising a multiplicity of cells interconnected so asto form a weblike barrier having vertical and horizontal dimensionrelative to the surface of said water, said barrier comprising at leasttwo horizontal rows of said interconnected cells, each of said cellshaving floatation and having at least three sides, extending verticallydown from the surface of said water, said cells being open at the topand bottom, said barrier being designed such that, upon partialsubmergence, water towards the top of said cells is at essentially zerohorizontal velocity;

b. weights coupled to said first boom for maintaining essentiallytwo-thirds of said first boom submerged in said water;

c. a tether boom;

d. lines connecting the top and bottom of the face of said first boom tosaid tether boom;

e. mooring floats;

f. pennants connected to said tether boom and said mooring floats; and

g. anchors coupled to said mooring floats.

1. An improved boom system for the containment of oil spills on thesurface of water, comprising in combination: a. A first boom comprisinga multiplicity of cells interconnected so as to form a weblike barrierhaving vertical and horizontal dimension relative to the surface of saidwater, said barrier comprising at least two horizontal rows of saidinterconnected cells, each of said cells being open at the top andbottom and comprising a vertically extending hollow segment offloatatable material, said barrier being designed such that, uponpartial submergence, the horizontal velocity of water towards the top ofsaid cells is considerably less than the current; b. weights coupled tosaid fist boom for maintaining said first boom partially submerged insaid water; c. a tether boom tied to said first boom; d. by lines whichconnect said first boom to said tether boom such as to maintain saidfirst boom essentially vertical relative to the surface of said water;and e. mooring means coupled to said tether boom.
 1. An improved boomsystem for the containment of oil spills on the surface of water,comprising in combination: a. A first boom comprising a multiplicity ofcells interconnected so as to form a weblike barrier having vertical andhorizontal dimension relative to the surface of said water, said barriercomprising at least two horizontal rows of said interconnected cells,each of said cells being open at the top and bottom and comprising avertically extending hollow segment of floatatable material, saidbarrier being designed such that, upon partial submergence, thehorizontal velocity of water towards the top of said cells isconsiderably less than the current; b. weights coupled to said fist boomfor maintaining said first boom partially submerged in said water; c. atether boom tied to said first boom; d. by lines which connect saidfirst boom to said tether boom such as to maintain said first boomessentially vertical relative to the surface of said water; and e.mooring means coupled to said tether boom.